Pooled analysis of efficacy and safety in Asian patients (pts) in the MONALEESA-2, MONALEESA-3, and MONALEESA-7 trials of ribociclib (RIB) plus endocrine therapy (ET)

Abstract

Background: We performed a pooled analysis of Asian pts in the phase III MONALEESA (ML) trials, which tested ET 6RIB in pts with hormone receptor-positive/human epidermal growth factor receptor-2-negative advanced breast cancer. Methods: ML-2 and ML-3 enrolled postmenopausal pts; ML-7 enrolled pre/perimeno-pausal pts. To pool a homogenous population and reflect health authority recommended treatment, this analysis included all pts from ML-2, first-line pts from ML-3 and pts treated with a nonsteroidal aromatase inhibitor from ML-7. Results: Pts were assignedtoET+ PBO (118 Asian; 562 non-Asian)or ET+RIB (136 Asian; 651 non-Asian). In Asian pts, median PFS was 12.7 mo (95% CI, 9.1-15.6) with PBO vsnot reached (NR; 95% CI, 16.6-NR) with RIB (hazard ratio [HR], 0.49 [95% CI, 0.34-0.70]). In non-Asian pts, median PFS was 16.5 mo (95% CI, 14.5-18.2) with PBO vs 25.3 mo (95% CI, 23.8-27.7) with RIB (HR, 0.59 [95% CI, 0.50-0.69]). In 182 Asian pts with visceral mets, median PFS was 12.7 mo (95% CI, 8.8-16.0) with PBO vs 23.9 mo (95% CI, 14.8-NR) with RIB (HR, 0.54 [95% CI, 0.36-0.82]). In 687 non-Asian pts with visceral mets, median PFS was 13.0 mo (95% CI, 11.1-14.9) with PBO vs 23.9 mo (95% CI, 19.9-29.6) with RIB (HR, 0.55; 95% CI, 0.44-0.68). In Asian pts, overall response rate (ORR) was 33.1% (95% CI, 24.6-41.5) with PBOvs 49.3% (95% CI, 40.9-57.7) with RIB (P = 0.005). In non-Asian pts, ORR was 27.8% (95% CI, 24.1-31.5) with PBO vs38.2% (95% CI, 34.5-42.0) with RIB (P<0.001). Among pts with visceral mets, ORR was 37.6% (95% CI 27.3-47.9) with PBO vs 52.6% (95% CI, 42.6-62.5) with RIB (P=0.022) inAsian and 34.5% (95% CI, 29.3-39.7) with PBO vs44.3% (95% CI, 39.2-49.4) with RIB (P=0.004)in non-Asian pts. The most common grade 3/4 adverse event (AE) was neutropenia (preferred term) in Asian (47.1%) and non-Asian (45.6%) RIB-treated pts. In the Asian subgroup, 1pt receiving PBO (0.8%) and 3 pts receiving RIB (2.2%) discontinued due to AEs; in non-Asian pts, 16 receiving PBO (2.8%) and 46 receiving RIB (7.1%) discontinued due to AEs. Conclusions: Significant improvements in PFS and ORR were observed in Asian pts with RIB vs PBO. Discontinuation rates due to AEs were lower in Asian pts.